[eigen] Eigen 3.4 release candidate 1!

[Christoph Hertzberg <chtz@xxxxxxxxxxxxxxxxxxxxxxxx>]

Hello Eigen users!

We are happy to announce the release of 3.4-rc1. This is a release 
candidate which is considered feature complete and only will get bug 
fixes until 3.4.0 is released.
This is not yet a stable release!

We encourage everyone, especially who is currently working with a 3.3 
version to try upgrading to 3.4-rc1 and report any regressions with any 
compilers and architectures you are using (this includes run-time 
errors, compile errors and compiler warnings).
Eigen should work with any C++ standard between C++03 and C++20, with 
GCC 4.8 (or later), Clang 3.3 (or later), MSVC 2012 (or later), and 
recent versions of CUDA, HIP, SYCL, on any target platform. If enabled 
by the compiler this includes SIMD vectorization for SSE/AVX/AVX512, 
AltiVec, MSA, NEON, SVE, ZVector.

To publish test results, you can run the unit tests as described here: 
[https://eigen.tuxfamily.org/index.php?title=Tests]
Please report issues until April 25th, or tell us if you are still in 
the process of testing.


The 3.4 release will be the last Eigen version with C++03 support.
Support of the 3.3 branch may soon be stopped.

The next major version will certainly also stop supporting some older 
compiler versions.


Regarding the version-numbering:
There was previously a 3.4 branch with recently was deleted again, as it 
was done prematurely and not properly kept up-to-date.
Unfortunately, this means that the version number (specified in 
Eigen/src/Core/util/Macros.h) had to be reset to 3.3.91 (the final 3.4 
release will have version 3.4.0). Version test macros will work 
incorrectly with any commit from master between 2021-02-17 and today. We 
apologize for any inconvenience this may cause.


Cheers,
Christoph





--
 Dr.-Ing. Christoph Hertzberg

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